Conventionally, electric therapeutic machines have been used as a sort of physical therapy, and a part of the electric therapeutic machine includes a low-frequency therapeutic apparatus which aims at treating a disease by applying electrodes on the surface of skin of a patient, and passing therewith a low-frequency current through the patient's body.
The low-frequency therapeutic apparatus comprises a therapeutic electrode (active electrode) applied on a site to be treated, and an inactive electrode to couple with the above electrode, and applying a low-frequency electric current between the two electrodes via a voltage delivered from an oscillator.
Such a low-frequency therapeutic apparatus is required, for example by Japanese Industrial Standards, to have an oscillator which can generate waves of at least one frequency for each of four bands of not more than 5 Hz, 5-50 Hz, 50-500 Hz and 500-1000 Hz.
Such a low frequency therapeutic apparatus has been used for the purpose of, for example, prevention of disuse atrophy of paralyzed muscles, pain relief and recovery of failed local blood circulation, through stimulation by way of electric currents. Furthermore, particularly a small low-frequency therapeutic apparatus has been used for relaxing stiffened shoulder muscles.
The conventional low-frequency therapeutic apparatuses as described above have been exclusively used for stimulation of muscles, pain relief, and recovery of failed circulation, but remains practically ineffective for the treatment of definitive diseases.